Interpretive Summary: Protocols for establishing plankton blooms in channel catfish production ponds have not been established. This study evaluated common fertilization practices used. Typically cotton seed waste and inorganic fertilizer (high in phosphorus) are used to stimulate algal blooms. Our work identified that ponds were nitrogen limited. Additions of 10:1 nitrogen:phosphorus provided sufficient nutrients for establishment of a plankton bloom.

Technical Abstract:
Fertilization practices in channel catfish fry ponds are not based upon research results. Typically farmers use cotton-seed waste and inorganic fertilizer (10-30-0) to establish plankton blooms. Results from this two-year study indicate that nitrogen limitation of algal biomass results from these practices. Little benefit is realized from the addition of the organic waste. Results from these studies indicate the need to fill ponds 7-10 days before stocking, and applying only inorganic fertilizer at an initial rate of approximately 20 kg/ha N and 2 kg/ha P, followed by subsequent applications twice weekly at one-half the initial rate.